Expanded Polypropylene Manhole Adjustment Rings
Manholes have traditionally been adjusted to final grade using brick, block and precast adjustment rings. Alternatives to these construction materials have entered the market over the years and the most recent to do so is an adjustment ring system manufactured from expanded polypropylene (EPP). The EPP material provides for the most advanced concrete-alternative manhole and catch basin grade adjustment system available today. EPP is renowned for its exceptional strength to weight ratio, durability, chemical resistance and long service life under harsh conditions. Available in round, square and rectangular shapes, one worker can install the EPP grade ring system in just minutes to within a quarter inch of finished grade without the use of mortar or shims. The rings are HS-25 traffic rated, are watertight, and, where concrete rings break and may cause injury, the EPP system eliminates the hazard, helping minimize the risk of injury. The EPP system dramatically speeds manhole installation or repair time and increases the life expectancy to 50 years or more.